Within a passenger compartment of a vehicle, many occupant restraint systems can be utilized, such as seatbelts and airbag systems. For instance, airbag systems can supplement the protection offered by seatbelts. Airbag systems typically comprise at least one folded airbag and an inflation gas. The airbag system is designed to inflate the airbag with the inflation gas when a collision between the vehicle and another object is detected.
Traditional airbag systems include driver-side airbags, passenger-side airbags, and side-impact airbags. Driver-side airbags are normally located in the steering column of the vehicle and passenger-side airbags are typically located in the dash board. Side-impact airbags include side cushion airbags, typically mounted in the outboard side of the seat, and side-curtain airbags, which are usually stored in the roof line and connected along the door frame.
Driver-side and passenger-side airbags often include vent holes to expel the inflation gas relatively quickly after inflation. Side-impact airbags including side curtain airbags, in contrast, remain inflated over long periods of time in order to offer prolonged protection in events such as roll-over crashes.
Usually, airbags are made of a woven fabric due to the substantial force the airbag must sustain from the inflating gas during deployment. Many different materials, either coated or uncoated, have been utilized in the manufacture of airbags, for example as described in U.S. Pat. Nos. 5,881,776 and 6,632,753, both of which are incorporated by reference herein.
Airbags in the past have been made using various techniques and processes. For example, in some applications, airbags are made by sewing together various panels. In other applications, instead of being made from separate panels, the airbags are made in a single weaving operation using, for instance, a Jacquard loom. Jacquard looms, for example, are capable of weaving together an airbag including a first side separated from a second side joined by a woven seam in one single operation, in a two dimensional structure. Such airbags are known in the art as “one-piece woven” airbags. One-piece woven airbags, however, are very expensive to produce, due to high levels of off quality in the weaving, coating and/or laminating process. For example, side curtains can require extensive levels of coating to allow for transition in the seams from plain to basket weave in the “binder” seam. One piece woven cushions also have inherent high cost due to high capital costs, overhead, and design support needed. Also, design changes are costly with new patterns and arrangements.
Expensive films of nylon or polyester can be used to produce airbags but are slow in processing and unreliable in adhesion levels.
Multi-piece airbags in the past have typically been made from a coated fabric. For instance, multi-piece airbags have been made from fabrics coated with a silicone or a neoprene. Although such fabrics can meet the permeability requirements needed for an airbag fabric, further improvements are needed.
For example, multi-piece airbags made from coated fabrics have a tendency to become damaged when inflated by an inflating mechanism. Inflating mechanisms used today, for instance, can generate hot gases that subject the airbag to significant forces. These forces can cause elongating or combing of the airbag fabric. Combing results when the yarns begin to fray and gases can leak along the sewn seam lines.
The present disclosure is directed to further improvements in airbag fabrics and in airbags made from the fabrics.